Hello Daman, I am just a fan of the game so don't consider anything that I write in any way official.
To your first two questions I'll confidently say yes. I have played all of the new characters as print and play versions with my base game and I can say that I, as a dedicated fan with 20+ games under my belt, find them mind-bogglingly good! The only problem I have with them (if you can call it that is that they make some of the Base game characters seem somewhat lack luster. The new time track and reward rules I also started applying straight when they came out and I never looked back. The other questions I cannot really answer but I know Blazej Kubacki the designer tends to lurk around these forums so don't be surprised if you get the answer straight from him at some point. Best Regards Nikolas